Fix for issue 1480: analyze a method even if it does not have a body, and do not try to evaluate ...

dart/frog/gen.dart

Index: dart/frog/gen.dart
===================================================================
--- dart/frog/gen.dart	(revision 3935)
+++ dart/frog/gen.dart	(working copy)
@@ -999,6 +999,10 @@
           // Ensure default value for param has been generated
           p.genValue(method, this);
           currentArg = p.value;
+          if (currentArg == null) {
+            // Not enough arguments, we'll get an error later.
+            return;
+          }
         }
       }